Along with the development of instant messaging technology, the use of instant messaging application software and mobile instant messaging application software is increasingly extensive. Presently, instant messaging application software is capable of supporting voice intercom function, and prior art method for activating the voice intercom function of instant messaging application software is as follows: user clicks the voice intercom button or the voice intercom function icon; mobile device initiates voice intercom function after detecting the user's click. Thereafter, the user achieves voice intercom by pressing and holding the voice intercom button or the voice intercom function icon, and cancels it by having his/her fingertip sliding upwards.
As the voice intercom button or the voice intercom function icon is located at a specific location on the touch screen, usually at the bottom of the touch screen, the user must press the touch screen at that specific location to be able to activate voice intercom function, and this causes inconvenience for the operation of activating the voice intercom function of instant messaging application software.